JPH07151261A - Electromagnetic proportional type pressure control valve - Google Patents

Abstract

PURPOSE:To prevent hunting, reduce dimension, with the simple structure at a low cost. CONSTITUTION:A pressure control valve is equipped with a sleeve 35 arranged on the inner peripheral surface of a housing 13, inside space 14 formed in the sleeve 35, inflow passage 16 and an effluence passage 18 which are formed on the housing 13, snap ring 15 arranged on the inflow passage 16 side on the inner surface of the sleeve 35, and a spool valve 19 which divides the inside space 14 to the inflow passage 16 and a pressure chamber 17. Further, the pressure control valve is equipped with an effluence hole 38 which is formed on the sleeve 35 and allows the inflow passage 16 and the effluence passage 18 to communicate and cuts off the flow when the top end of the spool valve 19 makes contact with the snap ring 15, throttle flow passage 20 which is formed on the spool valve 19 and allows the inflow passage 16 and the pressure chamber 17 to communicate, return hole 21 for the communication between the pressure chamber 17 and the effluence passage 18, plunger 22 which is formed midway in the return hole 21 and cuts off the communication between the pressure chamber 17 and the effluence passage 18, and an electromagnet part 12 for driving the plunger 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic proportional pressure control valve for an oil pump used in a vehicle engine cooling system or the like.

[0002]

2. Description of the Related Art As a conventional technique of this kind of electromagnetic proportional pressure control valve, there is known one disclosed in Japanese Patent Publication No. 5-73955. An inflow passage and an outflow passage provided in the housing, a fluid passage formed in the housing, and a valve seat provided on the inflow passage side of the fluid passage,
A control valve part having a bottomed cylindrical shape, which is arranged so as to face the valve seat and blocks communication between the inflow passage and the outflow passage when the tip comes into contact with the valve seat, and a cylindrical control valve part arranged inside the control valve part. A first pressure chamber formed by the rod portion, the inside of the cylindrical control valve portion and the head portion of the rod portion, a second pressure chamber formed by the bottom portion of the cylindrical control valve portion and the rod skirt portion, and a control valve A throttle passage formed at the bottom of the portion connecting the fluid passage and the first pressure chamber, a relief passage formed inside the rod portion connecting the first pressure chamber and the downstream of the control valve portion of the fluid passage, and formed in the middle of the escape passage And a first pressure chamber that includes a pilot valve portion that opens and closes the escape passage by contacting a pilot seat portion whose pressure receiving area is minute with respect to the valve seat portion, and an electromagnet that drives the pilot valve portion. Cylindrical control of the spill passage connecting the second pressure chamber Formed between the valve portion inner surface and the rod,
Moreover, the spill passage has a flow resistance of a predetermined value or more.

This is urged by the pressure in the inflow passage and the magnetic field generated by the coil in the direction in which the pilot valve portion is opened, so that the pressure in the first pressure chamber and the pressure in the outflow passage are balanced. The valve repeats opening and closing. At this time, the control valve portion also repeats opening and closing to connect the inflow passage and the outflow passage. Therefore, the differential pressure between the inflow passage and the outflow passage is kept constant. When the coil is repeatedly energized and de-energized in this way, the control valve section undergoes a rapid area change, so that the pressure in the first pressure chamber fluctuates significantly, causing hunting in the control valve section. . In order to prevent this hunting, a first pressure chamber and a second pressure chamber are formed, and the first pressure chamber and the second pressure chamber are communicated with each other by a spill passage having a predetermined flow resistance, and hunting due to pressure change is damped. It was prevented by the function.

[0004]

In the above-mentioned prior art, the structure is complicated due to the provision of the first pressure chamber, the second pressure chamber and the spill passage, and it is difficult to reduce the size. Further, the damper function acting by the first pressure chamber and the second pressure chamber changes depending on the oil temperature of the hydraulic oil because the spill passage is constant. For example, when the oil temperature is high, the damper function does not work because leakage from the spill passage increases, and when the oil temperature is low, the pilot valve is opened because the hydraulic oil in the second pressure chamber is hard to escape. However, since the responsiveness of opening the control valve part is delayed, abnormal hydraulic pressure is generated. Therefore, the hydraulic oil functions under a constant oil temperature condition, but otherwise the damper function does not work, and hunting cannot be prevented.

An object of the present invention is to prevent hunting with a simple structure and to reduce the size and cost.

[0006]

Means for Solving the Problems The measures taken in the present invention to solve the above-mentioned problems include a cylinder whose at least one end is open, an outflow passage communicating with the circumferential surface of the cylinder, and an outflow passage through the cylinder. A housing having an inflow passage communicating with the housing, an electromagnet portion coupled to the housing so as to liquid-tightly close one end of the housing, and an electromagnet portion having a plunger movable in the axial direction of the cylinder, and one closed end connected to the electromagnet portion. , Is located in the cylinder, the outer circumference of the other end is fluid-tightly fitted to the inner circumference of the cylinder, and a hole communicating with the outflow passage is formed in the peripheral wall. A sleeve forming a return passage communicating with the outflow passage, a sleeve slidably fitted on the inner circumference of the sleeve to form a pressure chamber with one end of the cylinder, and a sp Spool valve urged toward a predetermined position to block the hole from the inflow passage by a ring, a throttle passage formed in the spool valve to communicate the pressure chamber with the inflow passage, and a pressure chamber formed at the center of one end of the cylinder. Is connected to a return hole communicating with the return passage, and is urged by a spring to close the return hole against the pressure in the pressure chamber.When the electromagnet is excited, the action of the plunger is caused by a suction force. And a valve member that is displaced so as to open.

[0007]

According to the above-mentioned means, the spool valve formed on the sleeve for opening and closing the hole communicating with the outflow passage gradually opens the hole, so that the passage area does not change suddenly. Hunting of the spool valve is reduced because there is no pressure change. Further, since the return passage is formed by the inner peripheral surface of the housing and the outer peripheral surface of the sleeve, it is not necessary to provide the return passage, which leads to cost reduction. From the above, hydraulic oil corresponding to the water temperature of the engine cooling system is supplied to the hydraulic motor, and hunting can be prevented with a simple structure. Further, the size can be reduced and the cost can be reduced.

[0008]

Embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the electromagnetic proportional pressure control valve 10 is composed of a control valve portion 11 and an electromagnet portion 12, and the control valve portion 11 and the electromagnet portion 12 are integrally formed. . The control valve unit 11 will be described. The housing 13 of the oil pump 50 is provided with an inflow passage 16 that communicates with the discharge passage 51 of the oil pump 50, and an outflow passage 18 that returns the working oil to the suction side of the oil pump 50. A cylinder 39 is formed in the housing 13, and the inflow passage 16 and the outflow passage 18 can communicate with each other via the cylinder 39. Also, the cylinder 39
The sleeve 35 is inserted in the sleeve 35, and the sleeve 35 is fitted on the side of the inflow passage 16 so that the hydraulic oil does not leak. On the opposite side, a return passage 27 is formed by the outer peripheral surface of the sleeve 35 and the inner peripheral surface of the housing 13. The inflow passage 16 and the outflow passage 18 are connected by an outflow hole (hole) 38. Inside the sleeve 35,
An internal space 14 is formed, and a spool valve 19 that partitions the internal space 14 into an inflow passage 16 and a pressure chamber 17 is slidably accommodated. The spool valve 19 can open and close the outflow hole 38, and the movement amount is restricted by the snap ring 15 provided on the inflow passage 16 side of the sleeve 35. When the tip of the spool valve 19 comes into contact with the snap ring 15, the outflow hole 38 is closed. Further, the inflow passage 16 and the pressure chamber 17 are communicated with each other by a throttle passage formed in the spool valve 19. The pressure chamber 17 communicates with the outflow passage 18 through a return hole 21 formed in the sleeve 36 and a return passage 27.
Further, the outflow hole 38 is formed at one place on the circumference of the sleeve 35 in order to prevent the passage area of the outflow hole 38 from being rapidly changed, and the passage area gradually changes when the spool valve 19 is opened and closed. It is shaped like

The spool valve 19 is cylindrical and has a U-shaped cross section at one end, and is provided with a filter 24. Further, the filter 24 is fixed by a supporting member 25, and prevents foreign matter in the hydraulic oil from entering the pressure chamber 17. The throttle passage 20 of the spool valve 19 continuously connects the inflow passage 16 and the pressure chamber 17, and the inflow passage 16 and the pressure chamber 17 have the same pressure. or,
The other end of the spool valve 19 has an inverted U-shaped cross section. A return spring 26 for urging the outflow hole 38 in the direction of closing the outflow hole 38 is disposed at the inner peripheral end of the inverted U-shaped cross section.

The electromagnet section 12 will be described. The plunger 22 is arranged in the middle of the return hole 21. The plunger 22 includes a pilot valve 28, a rod 29,
And a plunger 30. Pilot valve 2
8 is integrally formed at one end of the rod 29, and the plunger 30 is also fixed at the other end by press fitting. The tip of the pilot valve 28 can open and close the return hole 21, and the rear end of the pilot valve 28 is in contact with one end of a spring 31 that urges the return hole 21 in the closing direction.
When the pilot valve 28 opens the return hole 21, the return hole 21 is connected to the communication passage 33 formed in the rod 29.
The hydraulic oil that has flowed out of the return hole 21 and communicates with the discharge hole 18 flows out into the outflow passage 18 via the communication passage 33 and the return passage 27. The other end of the spring 31 is in contact with the adjusting screw 32, and the urging force can be adjusted by the adjusting screw 32. The coil 23 that drives the plunger 30 is wound around the excited core 34.
The core 34 is arranged around the adjusting screw 32, and the guide core 37 is arranged between the adjusting screw 32 and the core 34.

As shown in FIG. 2, the electromagnetic proportional pressure control valve 10 is connected in parallel to the passage 51 of the oil pump 50, and the working oil discharged from the oil pump 50 flows out from the spool valve 19. When the hole 38 is in the closed state, the spool valve 19 flows through the discharge passage 51 and the outflow hole 38
When is open, it flows into the inflow passage 16 from the arrow A side and flows out from the outflow passage 18 in the direction of arrow B. A hydraulic motor 52 is connected to the oil pump 50, and a fan 53 is rotatably connected to the hydraulic motor 52. A radiator 54 is arranged in front of the fan 53. An ECU 56 that controls the electromagnetic proportional pressure control valve 10 by a signal 55 from a water temperature sensor is connected to the radiator 54.

Next, the operation of this embodiment will be described.

When a current corresponding to the signal 55 from the water temperature sensor is supplied to the coil 23 by the ECU 56, a magnetic field is generated. The pressure when the pilot valve 28 is opened / closed can be changed by the amount of current. The magnetic field excites the core 34 and tries to attract the plunger 30 to the core 34 side. When the suction force and the pressure of the pressure chamber 17 at this time are lower than the urging force of the spring 31, the pilot valve 28 closes the return hole 21. When the pressure in the pressure chamber 17 increases and becomes equal to the biasing force of the spring 31, the pilot valve 28 is in the neutral state and the spool valve 19 closes the outflow passage 18. The pressure receiving area of the pilot valve 28 is several steps smaller than the pressure receiving area of the spool valve 19. This allows the pilot valve 28 to slide even with an attractive force generated by a small current. By sliding the pilot valve 28, the spool valve 19 having a large pressure receiving area can be slid. When the pressure in the pressure chamber 17 increases and becomes higher than the biasing force of the spring 31, the pilot valve 28
Slides to the right in the drawing to open the return hole 28. When the return hole 28 is opened, the hydraulic oil is flown out to the outflow passage 18 via the communication passage 33 and the return passage 27. When the pressure chamber 17 and the outflow passage 18 communicate with each other, a differential pressure is generated between the inflow passage 16 and the pressure chamber 17. This is because the outflow amount outflowing from the throttle passage 20 is smaller than that of the return hole 21, so that the inflow passage 16 and the pressure chamber 17 are delayed in having the same pressure. When this pressure difference exceeds the biasing force of the return spring 26, the spool valve 19 also slides to the right in the figure. When the spool valve 19 slides, the outflow hole 38 is gradually opened, so that no sudden pressure change occurs. When the pressure in the inflow passage 16 decreases and the pressure difference with the pressure in the pressure chamber 17 disappears, and the pressure in the pressure chamber 17 decreases, the pilot valve 28 slides to the left side in the drawing due to the urging force of the spring 31. The return hole 21 is closed. When the return hole 21 is closed, the inflow passage 16 causes the spool valve 19 to slide to the left side in the drawing by the pressure of the pressure chamber 17 and the urging force of the return spring 26 to close the outflow hole 38. To do. Thereby, the discharge amount of the hydraulic oil discharged from the oil pump 50 can be linearly controlled.

As described above, when the spool valve 19 opens the outflow hole 38, there is no abrupt change in the passage area, so the pressure change in the pressure chamber 17 is small. Hunting of the valve 19 can be prevented. In addition, the control valve unit 11 and the electromagnet unit 1
It is possible to reduce the size by integrating 2 and 1 into an integrated structure.
Further, since the return passage 27 is formed by the outer peripheral surface of the sleeve 35 and the inner peripheral surface of the housing 13, it is not necessary to provide the return passage with a drill or the like. Therefore, hunting can be prevented with a simple structure, downsizing can be achieved, and the cost can be reduced.

[0016]

According to the invention described above, the spool valve for opening and closing the hole formed on the sleeve and communicating with the outflow passage is
Since the holes are gradually opened, there is no abrupt change in passage area, in other words, there is no abrupt pressure change.
Hunting of the spool valve is reduced. Further, since the return passage is formed by the inner peripheral surface of the housing and the outer peripheral surface of the sleeve, it is not necessary to provide the return passage, which leads to cost reduction. From the above, hydraulic oil corresponding to the water temperature of the engine cooling system is supplied to the hydraulic motor, and hunting can be prevented with a simple structure. Further, the size can be reduced and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an electromagnetic proportional pressure control valve according to an embodiment of the present invention.

FIG. 2 is a system diagram using an electromagnetic proportional pressure control valve.

[Explanation of symbols]

 10 ... Electromagnetic proportional pressure control valve 12 ... Electromagnet section 13 ... Housing 16 ... Inflow passage 17 ... Pressure chamber 18 ... Outflow passage 19 ... Spool valve 20 ... Throttle Passage 21 ... Return hole 22 ... Plunger 35 ... Sleeve 38 ... Outflow hole (hole) 39 ... Cylinder

Claims (1)

[Claims] 1. A housing having a cylinder having at least one end opened, an outflow passage communicating with a peripheral surface of the cylinder, and an inflow passage communicating with the outflow passage through the cylinder, and the one end of the housing is provided with a liquid. An electromagnet part which is coupled to the housing so as to be closed tightly and has a plunger movable in the axial direction of the cylinder, and a closed one end of which is connected to the electromagnet part and which is arranged in the cylinder and has an outer periphery of the other end. Is liquid-tightly fitted to the inner circumference of the cylinder, a hole communicating with the outflow passage is formed in the peripheral wall, and a return communicating with the outflow passage into the cylinder at an outer circumference extending from one end of the hole to one end. A sleeve forming a passage, slidably fitted to the inner circumference of the sleeve to form a pressure chamber between the sleeve and the one end of the cylinder, and a sleeve arranged in the pressure chamber. A spool valve biased toward a predetermined position to block the hole from the inflow passage by a pulling, a throttle passage formed in the spool valve to communicate the pressure chamber with the inflow passage, and a center of the one end of the cylinder A return hole that is formed in a portion and communicates the pressure chamber with the return passage, and is coupled to the plunger, and is urged by a spring to close the return hole against the pressure of the pressure chamber, and the electromagnet An electromagnetic proportional pressure control valve having a valve member that is displaced so as to open the return hole by an attractive force when the portion is excited.